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Recent experience with Borzit or Borit (tunneling) under a walkway

Here is my solution to a common problem:

Bought a Borit (Borzit) to go under a 22 foot concrete driveway slab. Didn't make it. Almost broke my wrist when the point seized on a large rock or something similar under the driveway at 8 feet. Lost the head, and had to order another. I have used a gas powered drill and electric low revolution, high torque drill motors to drive the bit. Was using the electric one when the point seized, and as I said, lucky I didn't break something.

Figured out a safer and somewhat easier method. Bought an old carpenders brace ( a hand powered "U" shaped apparatus used with wood bits) for $2 at a garage sale. Get one with a chuck large enough for the Borzit. You can control the speed and by pushing the handle with your chest, make slow steady progress. When I hit a rock or other obstruction, or when I just need more torque, I put a pipe wrench on the pipe, and turn manually.

In the Seattle area, our most common soil is "Glacial Till" a coarse sand with rounded 3 to 8 inch rocks in it. These tend to act like ball valves, when you push them out of the way, and then they fall back down in the path when the head is withdrawn. Makes pipe insertion difficult.

The above operation has worked under several sidewalks, but under the driveway, I had to sub it to a "bullet" operator. I have used their firm for direction drilling and th missile bullet boring. Best place to find a contractor is by calling the ditchwitch or other equipement dealer, and ask them for a reference. Prices vary, but most charge a minumum, here in the neighborhood of $300, which is more than I paid for my Borzit. Per foot charges vary on size of job and needs. I get a 2 inch sleeves with the directional drilling @ $10/foot, and bullet runs for $8/ft. As a repeat customer, I am charged a $200 minimum, and sometimes less if they can fit me in at the end of the day.

Bottom line. The Borit works on most tunneling operations. I think the hand brace idea imakes it safer (no electricity, no broken bones), and if used correctly, requires much less water than the "pipe technique". Less water means less material is removed under a walkway. This is important when tunneling under a driveway, or other surface that will bear considerable weight. You don't want a driveway to cave into your tunnel....bad form.

Jeff

This post has been edited 1 times, last edit by "Lowvolumejeff" (Sep 29th 2008, 12:43pm)

thanks

That's been my experience with boring in general. I haven't used this brand before. But I have used several in the past and I've always found most systems to be reliable for going under sidewalks, etc. but whenever I've tried to go under something long like a driveway, it never worked.

Nowadays, we just hire the directional boring company. They do it in 45 minutes with their $100K ditchwitch for $450.00. Quick and simple.